1. Field of the Invention
The present invention relates to a circulating lubrication oil passage structure of a toggle mechanism of an injection molding machine, more particularly one, which allows lubricating oil to circulate in a toggle mechanism consisting of upper and lower toggle assemblies for lubricating the pivotal joints of the toggle mechanism.
2. Brief Description of the Prior Art
Toggle devices are major mechanisms of injection molding machines. A toggle mechanism of an injection molding machine is usually fitted on a fixed support member and a movable mold support of the machine for moving the movable mold support so as to open/close the mold. Referring to FIG. 6, the inventor of the present invention developed an improvement (A) on a toggle mechanism of an injection molding machine once, which comprises a fixed support plate 1, a fixed toggle 10, a moving toggle 20, a pivotal rod 30, sleeves 40, and leakage prevention rings 50; the fixed toggle 10 is fitted on the fixed support plate 1; the moving toggle 20 has a pivotal hole 201, and is pivoted to the fixed toggle 10 by means of the pivotal rod 30; the sleeves 40 are fitted in the pivotal hole 201 of the moving toggle 20 and around the pivotal rod 30, and each have several oil guiding grooves 401 on an inner side, and lubricating oil is received between the pivotal rod 30 and the sleeves 40; furthermore, each of the sleeves 40 has annular recesses 402 on two ends of its inner side; the leakage prevention rings 50 are fitted on the annular recesses 402 for preventing lubricating oil from leaking out of the sleeves 40.
The above structure has a disadvantage: the toggle mechanism takes relatively much time and labor to maintain, and isn't convenient to use; because metal bits and tiny unwanted things will come into existence in the lubricating oil after the toggle mechanism has been used for a certain length of time, the pivotal rod has to be separated from the toggles for oil change regularly otherwise the toggle mechanism won't move smoothly.